JP5955214B2 - Battery module - Google Patents

Description

  The present invention relates to a technology capable of monitoring a temperature state of a battery cell efficiently and at low cost by a minimum temperature sensor in a battery module in which a plurality of battery cells made of lithium ion batteries are arranged in close contact.

As a battery module of a secondary battery represented by a lithium ion battery used for an electric vehicle or the like, an assembled battery of Patent Document 1 is known.
The assembled battery shown in Patent Document 1 has a structure in which a plurality of cell units formed by arranging a plurality of battery cells in series are arranged in parallel in a direction orthogonal to the direction in which the battery cells are arranged. A temperature sensor unit formed by connecting the temperature sensors at appropriate intervals is disposed on the side surface between the cell units.

  And by such a temperature sensor, the heat transfer distance with the electrode plate group of a battery cell is minimized, a heat transfer loss is made small, and abnormal temperature is detected appropriately.

JP 2001-91363 A

  By the way, in the battery module shown by patent document 1, it is the structure by which a temperature sensor is arrange | positioned so that it may be pinched | interposed between the battery cells of this cell unit in the cell unit formed by arrange | positioning several battery cells in series. Therefore, when the temperature detected by the temperature sensor is averaged and the overheat state determination temperature is set to the upper limit of the cell use temperature, it is accurately determined that any battery cell is overheated. There is a problem that it cannot be detected.

Moreover, in the said battery module, since the temperature sensor is arrange | positioned for every two battery cells, there exists a problem that a measurement point increases, As a result, wiring becomes complicated and cost becomes high.
Further, in the battery module, cooling air flows along the arrangement direction of the battery cells, but temperature measurement considering the cooling air is not performed, and there is still room for improvement in this respect. .

  The present invention has been made in view of the above-described circumstances, and the overheating state of the battery cell can be monitored efficiently and at a low cost by the minimum temperature sensor, and more accurate in consideration of cooling air. Provided is a battery module capable of measuring temperature and detecting an overheating state.

In order to solve the above problems, the present invention proposes the following means.
The present invention provides a cell unit in which a plurality of battery cells are arranged in close contact with each other, and a first temperature sensor that measures the temperature of any of the battery cells on one side surface along the arrangement direction of the battery cells. And a second temperature sensor for measuring the temperature of any battery cell other than the battery cell is provided on the other side surface opposite to the one side surface, and the battery cell is located between adjacent battery cells. It is characterized by being stacked via a heat conductive layer that promotes heat conduction.
Note that the close contact means that the adjacent electric cells in the cell unit do not directly contact each other, and between the adjacent battery cells, an electrically insulating sheet, a waterproof sheet, a separation sheet, On the contrary, it means a contact with an adhesive sheet or the like interposed. In particular, in the present invention, as a sheet for these purposes, a sheet having good thermal conductivity and not deteriorating thermal conductivity between battery cells, or a sheet having low thermal conductivity is used. .

In the invention configured as described above, for example, in consideration of the influence of cooling air, the first temperature sensor is disposed on one side surface of the battery cell having the highest temperature in the cell unit, and the second temperature sensor If the temperature sensor is disposed on the other side surface of the battery cell that is symmetrical to the first temperature sensor with respect to the center of the cell unit, and the detection values of these first and second temperature sensors are monitored, the cell unit It is possible to accurately know the temperature state of the battery cell inside.
In addition, since the first and second temperature sensors are provided on one side surface and the other side surface of the cell unit, respectively, the maximum temperature of the battery cell is monitored efficiently and at low cost by the minimum temperature sensor. In addition, the temperature can be accurately measured in consideration of the cooling air.
Furthermore, since the battery cells are stacked via a heat conductive layer that promotes heat conduction between adjacent battery cells, the heat conductive layer causes abnormal heat generation in any of the battery cells in the cell unit. When this occurs, abnormal heat is transmitted to the temperature sensor via the heat conductive layer between the battery cells. As a result, it is possible to quickly detect abnormal heat generation in a wide range of battery cells in the cell unit.

  In the present invention, a battery cell group connected to one battery cell whose temperature is measured by the one temperature sensor, and a battery cell group connected to another battery cell whose temperature is measured by the other temperature sensor. A low thermal conductive layer having a lower thermal conductivity than the thermal conductive layer is provided therebetween.

  In the invention configured as described above, the battery cell group is connected to one battery cell whose temperature is measured by one temperature sensor, and is connected to another battery cell whose temperature is measured by the other temperature sensor. Since the low thermal conductive layer having lower thermal conductivity than the thermal conductive layer is provided between the battery cell group, the low thermal conductive layer is interposed between the battery cell group on one side and the battery cell on the other side. Heat transfer between groups is inhibited. Thus, for example, abnormal heat generated in one battery cell group is difficult to be transmitted to the other battery cell group, and the detected value of the temperature sensor installed in the one battery cell group and the other battery cell The temperature difference between the detection value of the temperature sensor installed in the group and the detection value of the temperature sensor of another cell unit becomes large, and based on this temperature difference, it is possible to easily detect the abnormality of the battery cell in the unit cell. It becomes possible.

  In the present invention, the arrangement direction of the battery cells in the cell unit is directed to the direction in which the cooling air flows.

  In the present invention, the one temperature sensor is provided in the Nth battery cell from one end in the arrangement direction of the battery cells, and the other temperature sensor is provided in the Nth battery cell from the other end in the arrangement direction. Features.

  Further, in the present invention, the first temperature sensor is disposed on one side surface of the battery cell having the highest temperature in the cell unit, and the second temperature sensor is located on the center of the cell unit. It arrange | positions at the other side surface of the battery cell symmetrical with a 1st temperature sensor, It is characterized by the above-mentioned.

  Further, in the present invention, the first temperature sensor is disposed on one side surface of the battery cell behind the center portion among the plurality of battery cells disposed in the direction of flowing along the cooling air. It is characterized by being.

In the invention configured as described above, the first temperature sensor is arranged on one side surface with respect to the arrangement direction of the cell units, and the first temperature sensor is arranged along the direction in which the cooling air flows. The second temperature sensor, which is the other temperature sensor, is positioned on the other side surface of the Nth battery cell from the other end in the arrangement direction. As a result, the Nth battery cell is set as the cell having the highest temperature in the cell unit, the first temperature sensor is arranged in the Nth battery cell, and the Nth battery from the other end in the arrangement direction. By disposing the second temperature sensor in the cell, the first temperature sensor and the second temperature sensor can be installed at positions symmetrical to the first temperature sensor with respect to the center of the cell unit. . In this state, if the detection values of the first and second temperature sensors are monitored, the temperature state of the battery cell in the cell unit can be accurately known.
In addition, the first temperature sensor is installed in the Nth battery cell from one end in the arrangement direction of the battery cells, and the second temperature sensor is installed in the Nth battery cell from the other end in the arrangement direction. Even if cooling air flows from either side along the cell arrangement direction, it is possible to know the temperature status of the battery cells in the cell unit under the same conditions. It becomes possible to monitor the overheating state of the battery cell at a cost.

  In the present invention, there are a plurality of the cell units, and the plurality of cell units are connected in series.

  In the present invention, there are a plurality of the cell units, and the plurality of cell units are connected in parallel.

  In the present invention, a cooling fan for circulating cooling air is installed at an end of the battery pack case in which the plurality of cell units are accommodated.

And in the invention configured as described above, there are a plurality of cell units, and the plurality of cell units are configured to be connected in series or in parallel, so in each of these cell units connected in series or in parallel, It is possible to accurately know the temperature state of the battery cell. As a result, the temperatures detected by a plurality of cell units are compared, and if there is a variation in the temperatures, the unit cell in which the variation has occurred can be determined to be abnormal, and accurate temperature abnormality detection can be performed.
In addition, by providing a cooling fan at the end of the battery pack case in which the plurality of cell units are accommodated, cooling air can be forced to flow in the battery pack case, and a high cooling effect can be obtained. it can.

  According to the present invention, in consideration of the influence of cooling air, the first temperature sensor is arranged on one side surface of the battery cell having the highest temperature in the cell unit, and the second temperature sensor is arranged at the center of the cell unit. If it is arranged on the other side surface of the battery cell that is symmetrical to the first temperature sensor with respect to the part, and the detection values of these first and second temperature sensors are monitored, the temperature status of the battery cell in the cell unit can be determined. Know exactly.

  In addition, since the first and second temperature sensors are provided on each of the one side surface and the other side surface of the cell unit, the overheating state of the battery cell is monitored efficiently and at low cost with the minimum temperature sensor. In addition, the temperature can be accurately measured in consideration of the cooling air.

  Further, since the battery cells are stacked via a heat conductive layer that promotes heat conduction between adjacent battery cells, the temperature difference between the cells can be reduced by the heat conductive layer. As a result, when abnormal heat generation occurs in any one of the battery cells in the cell unit, the abnormal heat generation is transmitted to the temperature sensor through the heat conduction layer between the battery cells. As a result, it is possible to quickly detect abnormal heat generation in a wide range of battery cells in the cell unit.

1 is a schematic configuration diagram showing a power management device in which a plurality of battery modules according to a first embodiment of the present invention are incorporated. It is a perspective view which shows the assembled battery incorporated in the power management apparatus of FIG. It is a front view which shows the battery module in which the heat conductive layer of high heat conductivity was interposed between the battery cells. It is a graph which shows the temperature distribution for every battery cell of a battery module. It is a top view which shows the arrangement | positioning state of the temperature sensor in one battery module. It is a front view which concerns on 2nd Embodiment of this invention and shows the battery module by which the low heat conductive layer was interposed between the intermediate | middle battery cells. It is a top view which shows the state which concerns on 3rd Embodiment of this invention and the battery module was arrange | positioned in series in the battery pack case. It is a top view which shows the state which concerns on 3rd Embodiment of this invention and the battery module was arrange | positioned in parallel in the battery pack case.

(First embodiment)
1st Embodiment which concerns on this invention is described with reference to FIGS.
FIG. 1 is a diagram showing a power management device 10 in which a plurality of battery modules 40 according to the present invention are incorporated. FIG. 2 is a perspective view showing an assembled battery 100 in which the battery modules 40 are integrated. 10 includes a plurality of battery units 20-1 to 20-m.

  Each battery unit 20 includes one BMU (Battery Management Unit) 30 serving as an upper management unit, and a plurality of battery modules 40 (in this example, six sets of 40-1 to 40-6). Each of the BMU 30 and the battery module 40 is connected via a communication bus 31A so that mutual communication is possible. Further, the BMU 30 manages the battery module 40 in each power supply unit 20 via the communication bus 31B.

Moreover, each battery module 40 is provided with one CMU (Cell Monitoring Unit) 32 for every battery cell C1-C8 with eight battery cells C1-C8, as FIG. 2 shows.
Each of the battery cells C1 to C8 is a single secondary battery, for example, a lithium ion battery is adopted, but the type as the secondary battery is not particularly limited. Further, the CMU 32 controls each charge / discharge operation in the battery cells C1 to C8 based on the temperature detected by the battery cells C1 to C8 (detected by the temperature sensors 60 and 61). The CMU 32 is connected to the communication buses 31A and 31B so as to be communicable with the BMU 30.

Next, with reference to FIG. 2, the assembled battery 100 in the battery unit 20 in which a plurality of battery modules 40 are accommodated and integrated will be described.
In this assembled battery 100, a plurality of battery modules 40 (consisting of six sets of battery modules 40-1 to 40-6 in this example) are accommodated in parallel in a battery pack case 50 having a rectangular shape as a whole. Is.
Each battery module 40 includes a cell unit 41 in which eight battery cells C1 to C8 are in close contact with each other via a heat conductive layer 70 (described later), and each battery cell C1 to C8 is an upper surface of the battery container 42. In this configuration, electrode terminals 43 and 44 are provided. The battery cells C1 to C8 are formed in a rectangular parallelepiped as a whole, and are arranged so that the directions of the long side 42A and the short side 42B coincide with each other and the battery containers 42 are in surface contact with each other. The cell units 41 of the battery modules 40 are configured to be integrated with a binding band 46 in a state where the fixing plates 45 are installed at both ends of the eight battery cells C1 to C8 that are in close contact with each other.
In the following description, a unit in which eight battery cells C1 to C8 are closely attached and integrated with each other by the binding band 46 and the fixing plate 45 is defined as a “cell unit 41”. A device provided with a temperature sensor 60 (described later) and a second temperature sensor 61 (described later) is defined as a “battery module 40”.

In the assembled battery 100, cooling air that cools the battery module 40 flows between the battery module 40 and the other battery modules 40 and between the battery module 40 and the wall surface of the battery pack case 50.
This cooling air flows along the arrangement direction of the battery cells C1 to C8 (directions indicated by arrows (A) to (B)) in the battery module 40 as indicated by the symbol F, and thereby the cell unit 41 Both side surfaces consisting of one side surface (indicated by reference numeral 41A) and the other side surface (indicated by reference numeral 41B) are cooled.

With reference to FIG. 3, the cell unit 41 in the battery module 40 will be described in more detail.
As shown in FIG. 3, the cell unit 41 is stacked between adjacent battery cells C <b> 1 to C <b> 8 with a heat conductive layer 70 that promotes heat conduction of the battery cells C <b> 1 to C <b> 8 interposed therebetween.

  The heat conductive layer 70 prevents an extreme temperature difference between the battery cells C1 to C8 by promoting heat conduction between the adjacent battery cells C1 to C8. On the other hand, in the case where abnormal heat generation (indicated by symbol H) occurs in any of the battery cells C1 to C8 in the cell unit 41, the heat conduction layer 70 converts the abnormal heat generation H to the adjacent battery cells C1 to C8. The heat is transferred to the temperature sensors 60 and 61 via. Accordingly, these temperature sensors 60 and 61 can detect abnormal heat generation in a wide range of battery cells C1 to C8 in the cell unit 41.

The heat conductive layer 70 is made of a material having a low thermal resistance such as an electrically insulating material having a good heat conductivity, such as a heat radiating silicon sheet.
Further, by interposing the heat conductive layer 70 between the battery cells C1 to C8, the temperature difference between the battery cells C1 to C8 can be reduced and the temperature distribution can be made smooth. The measurement result of may not exceed the use limit of the battery cells C1 to C8. For this reason, lowering the abnormality determination threshold value than other normal module batteries, or the temperature difference with other module batteries It responds by detecting the increase.

Next, with reference to FIG. 4, the temperature distribution of the eight battery cells C1 to C8 constituting the battery module 40 will be described.
As shown in FIG. 2, when cooling air F flows in the direction of arrows (A)-(B) from the battery cell C1 toward the battery cell C8, the battery cells C1 to C8 are cooled from both side surfaces 41A and 41B, respectively. However, since the cooling air F is gradually warmed each time it passes through the upstream battery cells C1 to C8, the temperature of each of the battery cells C1 to C8 varies.

This is summarized in FIG. As can be seen with reference to this figure, it was found that the sixth (= Nth) temperature is the highest among the battery cells C1 to C8 installed in the direction in which the cooling air F flows (the highest temperature). The battery cell is indicated by N). Even if the number of the battery cells C is different, the same tendency appears, and among the plurality of battery cells arranged in the direction of flowing along the cooling air F, the battery cell (N = The sixth temperature is the highest.
Therefore, in the present embodiment, as shown in FIG. 5, the first temperature is applied to one side surface 41A of the sixth (= Nth) temperature cell C6 having the highest temperature among the battery cells C1 to C8. A sensor 60 is installed. At the same time, the second temperature sensor 61 is installed in the battery cell on the other side surface 41B facing the one side surface 41A of the battery module 40 and at any position other than the battery cell C6.

The second temperature sensor 61 is provided on the other side surface 41B of the battery cell (in this example, the Nth battery cell C3 from the right end) that is symmetrical to the first temperature sensor 60 with respect to the central portion X of the cell unit 41. Is arranged.
And by installing such temperature sensors 60 and 61, the cooling air F flows from either side (upstream side or downstream side) along the arrangement direction (arrows (A) to (B)) of the battery cells C1 to C8. Even if it is, the temperature conditions of the battery cells C1 to C8 in the cell unit 41 can be accurately known under the same conditions. As a result, the maximum cell temperatures of the battery cells C1 to C8 can be monitored efficiently and at low cost by the minimum temperature sensors 60 and 61 (two in this example).

As described in detail above, in the battery module 40 shown in the present embodiment, the first temperature sensor 60 is arranged in the cell unit 41 arranged along the direction in which the cooling air F flows, in the arrangement direction of the battery cells C1 to C8. (Arrow (B)-(B) direction) Nth (= battery cell C6) from one end and the second temperature sensor 61 is Nth (= battery cell C3) battery cell from the other end in the arrangement direction. It was located on the other side surface 41B.
Here, the Nth (= battery cell C6) in which the first temperature sensor 60 is disposed is the battery cell C6 having the highest temperature in the cell unit 41, and also. The second temperature sensor 61 is a battery cell C3 that is in a symmetrical position with the first temperature sensor 60.
Thereby, even if the cooling air F flows from any side (upstream side or downstream side) along the arrangement direction (arrow (A)-(B) direction) of the battery cells C1 to C8, the cell unit under the same conditions. It is possible to accurately know the temperature state of the battery cells C1 to C8 in the battery 41, and it is possible to monitor the maximum cell temperature of the battery cells C1 to C8 efficiently and at low cost with this minimum temperature sensor. Become.

  That is, in the battery module 40 shown in the present embodiment, the number of temperature measurement points can be reduced as compared with the conventional case, the arrangement of the module battery is switched back and forth, and the cooling air F is on the battery cell C1 side or the battery cell C8 side. The maximum battery cell temperature can be measured without changing the installation position even if it flows from the battery, and it is possible to save wiring and reduce costs compared to conventional battery modules in which temperature sensors are installed in all battery cells. .

  Moreover, since the battery module 40 shown by this embodiment is the structure on which the battery cells C1-C8 were piled up via the heat conductive layer 70 which accelerates | stimulates the heat conduction between the adjacent battery cells C1-C8, this The heat conductive layer 70 can prevent an extreme temperature difference between the battery cells C1 to C8. Further, when abnormal heat generation H occurs in any of the battery cells C1 to C8 in the cell unit 41, the abnormal heat generation H is transmitted to the temperature sensor via the heat conduction layer 70 between the battery cells C1 to C8. . Thereby, when the detection value of the temperature sensor exceeds the abnormality determination threshold value or the difference from the detection value of the temperature sensor of another module battery becomes large, the battery cells C1 to C8 in a wide range in the cell unit 41 It becomes possible to quickly detect a heat generation abnormality.

In the above embodiment, an example in which six battery modules 40 (consisting of six sets 40-1 to 40-6) are provided in the battery unit 20 is shown in FIG. The number can be set as appropriate.
Moreover, although the cell unit 41 of the battery module 40 was comprised by the eight battery cells C1-C8, this is an example and the number can be set suitably. In addition, among the eight battery cells C1 to C8, the first temperature sensor 60 is installed on one side surface 41A of the sixth (= Nth) temperature cell C6 having the highest temperature. This is because among the plurality of battery cells arranged in the direction of flowing along the cooling air F, the temperature of the battery cell (N = 6th in this example) behind the center is the highest, When the number of battery cells is not eight, for example, when the number of battery cells in the cell unit 41 is ten, “N = 7th” is selected.

(Second Embodiment)
A second embodiment according to the present invention will be described with reference to FIG.
The battery module 40 of the second embodiment is different from the battery module 40 of the first embodiment in the structure of the cell unit 41 in the battery module 40.

In the cell unit 41 in the battery module 40 shown in FIG. 6, a heat conductive layer 70 that promotes heat conduction of the battery cells C1 to C8 is interposed between adjacent battery cells C1 to C8, and the battery cell C1. The intermediate part of .about.C8 is provided with a low thermal conductive layer 71 having a thermal conductivity lower than that of the thermal conductive layer 70 instead of the thermal conductive layer 70.
That is, in the cell unit 41 in FIG. 6, one battery cell C <b> 5 whose temperature is measured by one temperature sensor 60 while the heat conduction layer 70 that promotes heat conduction is interposed between the adjacent battery cells C <b> 1 to C <b> 8. ~ C8 group and the other battery cells C1 to C4 group whose temperature is measured by the other temperature sensor 61, instead of the heat conductive layer 70, is relatively more thermally conductive than this heat conductive layer 70. A low thermal conductive layer 71 having a low thickness is provided.

A rubber sheet is generally used for the low heat conductive layer 71. However, when it is necessary to relatively reduce the heat conductivity (high heat insulation is required) as in this embodiment, for example, a sheet is used. You can make it thicker.
And in the cell unit 41 in the battery module 40, by providing the low thermal conductive layer 71 with low thermal conductivity between the battery cells C5 to C8 and the battery cells C1 to C4, heat between these cell groups can be obtained. Transmission is inhibited.

  As a result, for example, abnormal heat generation H generated in the battery cells C5 to C8 on one side is difficult to be transmitted to the battery cells C1 to C4 on the other side, and the temperature installed in the battery cells C5 to C8 on the one side The temperature difference between the detection value of the sensor 60 and the detection value of the temperature sensor 61 installed in the other battery cell group C1 to C4 increases, and based on this temperature difference, the battery cells C1 to C8 in the unit 41 cell. Abnormalities can be easily detected.

  The temperature difference between the battery modules 40 varies depending on the installation location of each battery module 40. Therefore, it is necessary to provide a margin for the temperature difference abnormality detection value. In the case of the method shown in FIG. Since abnormality detection is performed by temperature measurement comparison between the battery cells C1 to C4 and the battery cells C5 to C8 that are thermally separated in one battery module 40, the temperature abnormality can be detected more sensitively. Can do.

As described above in detail, in the battery module 40 shown in the present embodiment, the battery cell C1 to C8 group connected to one battery cell C1 to C8 whose temperature is measured by the temperature sensor 60, and the other temperature sensor 61. Since the low thermal conductive layer 71 having lower thermal conductivity than the thermal conductive layer 70 is further provided between the battery cells C1 to C8 connected to the other battery cells C1 to C8 whose temperature is measured by By interposing the layer 71 therebetween, heat transfer between the battery cells C1 to C4 on one side and the battery cells C6 to C8 on the other side is inhibited.
Thereby, for example, the abnormal heat generation H generated in the battery cells C6 to C8 on one side is not easily transmitted to the battery cells C1 to C4 on the other side, and the temperature installed in the battery cells C6 to C8 on the one side The temperature difference between the detection value of the sensor 60 and the detection value of the temperature sensor 61 installed in the other battery cell group C1 to C4 increases, and based on this temperature difference, the battery cells C1 to C8 in the unit 41 cell. Abnormalities can be easily detected.

  In addition, in this embodiment, although the low heat conductive layer 71 is provided between one battery cell C5-C8 group and the other battery cell C1-C4 group, the installation location is battery cell C4 and C5. It is not limited to between, and it can change suitably.

(Third embodiment)
A third embodiment according to the present invention will be described with reference to FIGS.
The assembled battery 101 of the third embodiment is different from the assembled battery 100 of the first and second embodiments in that the battery modules 40 are arranged in series or in parallel, and the cooling air F is applied to the end of the battery pack case 50. This is the point that a cooling fan 51 forcibly circulating is provided.

In the battery pack case 50 shown in FIG. 7, a plurality of battery modules 40 are arranged in series and arranged so as to be folded in the middle to form two rows.
Further, in the battery pack case 50 shown in FIG. 8, a plurality of battery modules 40 are arranged so that three battery modules 40 are connected in parallel in two rows.

Further, as shown in FIGS. 7 and 8, a cooling fan 51 is installed at the rear end of the battery pack case 50, and cooling air F is sucked into the front end of the battery pack case 50. A mouth 52 is provided.
When the cooling fan 51 is driven, the cooling air F sucked from the air inlet 52 flows in the arrow (b) direction along the arrangement direction of the battery cells C1 to C8. As a result, the battery module 40 Is cooled.

In addition, each battery module 40 in the battery pack case 50 is provided with the first temperature sensor 60 and the second temperature sensor 61 described in the first and second embodiments.
The first temperature sensor 60 is installed on the side surfaces 41A and 41B of the temperature cell C6 or C3 having the highest temperature among the battery cells C1 to C8. The second temperature sensor 61 is installed on the side surfaces 41 </ b> A and 41 </ b> B of the battery cell C <b> 3 or C <b> 6 that is symmetrical to the first temperature sensor 60 with respect to the center portion X of the cell unit 41.
And by installing such temperature sensors 60 and 61, the cooling air F flows from either side (upstream side or downstream side) along the arrangement direction (arrows (A) to (B)) of the battery cells C1 to C8. Even if it is, the temperature conditions of the battery cells C1 to C8 in the cell unit 41 can be accurately known under the same conditions.

  In addition, in each of the cell units 41 in which the battery modules 40 are connected in series or in parallel, the temperature status of the battery cells C1 to C8 can be detected, so the temperatures detected by the plurality of cell units 41 are compared. If there is a variation in these temperatures, the unit cell 41 in which the variation has occurred or its cooling mechanism can be determined to be abnormal, and accurate temperature abnormality detection can be performed.

The following processing is performed as a specific abnormality determination method.
(1) Whether the temperature difference with the upstream battery module 40 exceeds a design value (for example, 2 ° C.) is “0” (normal within the design value range) or “1” (abnormal when the design value is exceeded) The digital value is ORed for each column of the battery module 40, and when it is “1”, it is determined that the column is abnormal.
(2) The measurement values of the temperature sensors 60 and 61 at the same position between the rows of the battery modules 40 are compared, and a determination value based on battery cell heat generation and variation in the cooling flow path is set (for example, the determination value is set to 5 ° C.). ). And when the dispersion | variation in the measured value of temperature sensor 60 * 61 becomes more than this determination value, it determines with the battery module 40 having abnormality.
(3) The temperature gradient between the columns of the battery modules 40 is calculated, and if there is a difference compared with other columns, it is determined that the column is abnormal. The abnormality determination of the battery module 40 is performed by the process as described above.

As described above in detail, in the third embodiment, in each of the plurality of battery modules 40 accommodated in the battery pack case 50, the temperature cell C6 or C3 having the highest temperature among the battery cells C1 to C8. The first temperature sensor 60 is installed on the side surfaces 41A and 41B, and the second temperature sensor 61 is a battery cell C3 or C6 that is symmetrical to the first temperature sensor 60 with respect to the central portion X of the cell unit 41. The second temperature sensor 61 was installed on the side surfaces 41A and 41B.
Thereby, even if the cooling air F flows from any side (upstream side or downstream side) along the arrangement direction (arrow (A)-(B) direction) of the battery cells C1 to C8, the cell unit under the same conditions. It is possible to accurately know the temperature status of the battery cells C1 to C8 in the battery 41, and it is also possible to monitor the overheating status of the battery cells C1 to C8 efficiently and at low cost with this minimum temperature sensor. .
In addition, in each of the cell units 41 in which the battery modules 40 are connected in series or in parallel, the temperature status of the battery cells C1 to C8 can be detected, so the temperatures detected by the plurality of cell units 41 are compared. If there is a variation in these temperatures, the unit cell 41 in which the variation has occurred or its cooling mechanism can be determined to be abnormal, and accurate temperature abnormality detection can be performed.

  As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.

  The present invention relates to a technology capable of monitoring a temperature state of a battery cell efficiently and at low cost by a minimum temperature sensor in a battery module in which a plurality of battery cells made of lithium ion batteries are arranged in close contact.

40 battery module 41 cell unit 41A one side surface 41B other side surface 50 battery pack case 51 cooling fan 60 first temperature sensor 61 second temperature sensor 70 heat conduction layer 71 low heat conduction layer C1 to C8 battery cell X center ( B) Cell orientation

Claims (8)

A cell unit in which a plurality of battery cells are placed in close contact with each other, and
The first temperature sensor that measures the temperature of any one of the battery cells on one side surface along the arrangement direction of the battery cells, and any one other than the battery cell on the other side surface that faces the one side surface. A second temperature sensor for measuring the temperature of the battery cell of
The battery cells are stacked via a heat conductive layer that promotes heat conduction between adjacent battery cells ,
The heat conductive layer between a battery cell group connected to one battery cell whose temperature is measured by the one temperature sensor and a battery cell group connected to another battery cell whose temperature is measured by the other temperature sensor. A battery module comprising a low thermal conductive layer having lower thermal conductivity . The battery module according to claim 1 , wherein the arrangement direction of the battery cells in the cell unit is directed in a direction in which cooling air flows. Temperature sensor of the one is the N-th battery cell from the array direction end of the battery cell, the other temperature sensors, claims, characterized in that provided from the array direction end to the N-th battery cell 1 Or the battery module of any one of 2 . The first temperature sensor is disposed on one side surface of the battery cell that has the highest temperature in the cell unit,
The second temperature sensor of any of claims 1 to 3, characterized in that disposed on the other side surface of the first temperature sensor and symmetric to become cells with respect to the center portion of the cell unit The battery module according to item 1. Said first temperature sensor, a request to among the plurality of battery cells arranged in the direction of flow along the cooling air, characterized in that it is arranged from the central portion on one side surface of the rear of the battery cell Item 5. The battery module according to Item 4 . The battery module according to claim 1 , wherein there are a plurality of the cell units, and the plurality of cell units are connected in series. The battery module according to claim 1 , wherein there are a plurality of the cell units, and the plurality of cell units are connected in parallel. 8. The battery according to claim 6, wherein a cooling fan for circulating cooling air is installed at an end of the battery pack case in which the plurality of cell units are accommodated. module.

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